G protein-coupled receptors (GPCR) are seven-transmembrane receptors and are responsible for actions to transduce the signal of hormones, neurotransmitters, cytokines and other molecules, across the cell membrane.
Human GPR35 (Non-Patent Publication 1: Genomics, 47, 310-313, 1988) is one of GPCR, for which no ligand has not been reported. It is reported that the cDNA fragments of GPR35 extracted from human gastric cancer are speculated to have transformation activities in NIH3T3 cells (Non-Patent Publication 2: Cancer Science, 95, 131-135, 2004).
6,7-Dinitroquinoxaline-2,3-dione is known as a N-methyl-D-aspartic acid (NMDA) antagonist acting on glutamate receptors (Non-Patent Publication 3: International Review of Neurobiology, 32, 281-303, 1990).
Ellagic acid is a naturally occurring polyphenol contained in strawberries or the like and known to have physiological actions including an anticarcinogenic activity (Non-Patent Publication 4: Mutation Research, 202, 429-446, 1988), an antioxidant activity (Non-Patent Publication 5: Biochemical Pharmacology, 42, 1441-1445, 1991), etc.